34 



LIX. The Lamp or Candle Flame. 



1. What part of the flame gives forth most light ? Sketch the 

 flame. 



2. By lowering- a sheet of white paper upon the flame find at what 

 part the flame is hottest by observing- the areas scorched. 



3. What is the use of the wick ? Is it consumed ? 



4. Determine all that happens when a fine wire g-auze is lowered 

 upon a flame. Explain the phenomena. 



6. Have you evidence that there is a g-radual conversion of the solid 

 tallow into a liquid, then into g-as, before it burns? 



6. How can you show that free Carbon is present in the luminous 

 part of the flame? Explain the "smoking-" of a lamp or. gas jet. 



7. How can you show that without air a candle will not burn ? 

 Account for the presence of the holes in the base of a lamp-burner. 



8. Show that carbon dioxide gas is formed when a candle burns. 



LX. A Snow Storm. 



1. What causes snow ? 



2. At what temperature do snow crystals form ? 



3. How do the clouds appear before a snow storm ? 



4. What is the temperature of the air before the storm? 



5. What is the direction of the wind before the storm ? 



6. Does the storm come in the- same direction as the wind ? 



7. What are the conditions of the wind and temperature when the 

 snow crystals are most perfect in form ? 



8. What are these conditions when the snow crystals are matted to- 

 gether in great flakes ? 



9. What are these conditions when the snow crystals appear sharp 

 ■ and needle-like? 



10. Are the snow crystals of the same storm similar in structure and 

 decoration ? 



11. What is the difference in structure between a snowflake and a 

 hailstone? 



12. What is sleet ? 



13. What is the difference between hoar frost and snow ? 



14. Does the temperature rise or fall during a snow storm ? 



15. Is it colder or warmer after a storm has passed than it was before 

 it began ? 



16. What are the conditions of weather which cause a blizzard? 

 17. Why does a covering of snow prevent the ground from freezing so 

 severely as it would if bare ? 



